js/controllers/autoanimate.js
import { queryAll, extend, createStyleSheet, matches, closest } from '../utils/util.js'
import { FRAGMENT_STYLE_REGEX } from '../utils/constants.js'
// Counter used to generate unique IDs for auto-animated elements
let autoAnimateCounter = 0;
/**
* Automatically animates matching elements across
* slides with the [data-auto-animate] attribute.
*/
export default class AutoAnimate {
constructor( Reveal ) {
this.Reveal = Reveal;
}
/**
* Runs an auto-animation between the given slides.
*
* @param {HTMLElement} fromSlide
* @param {HTMLElement} toSlide
*/
run( fromSlide, toSlide ) {
// Clean up after prior animations
this.reset();
let allSlides = this.Reveal.getSlides();
let toSlideIndex = allSlides.indexOf( toSlide );
let fromSlideIndex = allSlides.indexOf( fromSlide );
// Ensure that;
// 1. Both slides exist.
// 2. Both slides are auto-animate targets with the same
// data-auto-animate-id value (including null if absent on both).
// 3. data-auto-animate-restart isn't set on the physically latter
// slide (independent of slide direction).
if( fromSlide && toSlide && fromSlide.hasAttribute( 'data-auto-animate' ) && toSlide.hasAttribute( 'data-auto-animate' )
&& fromSlide.getAttribute( 'data-auto-animate-id' ) === toSlide.getAttribute( 'data-auto-animate-id' )
&& !( toSlideIndex > fromSlideIndex ? toSlide : fromSlide ).hasAttribute( 'data-auto-animate-restart' ) ) {
// Create a new auto-animate sheet
this.autoAnimateStyleSheet = this.autoAnimateStyleSheet || createStyleSheet();
let animationOptions = this.getAutoAnimateOptions( toSlide );
// Set our starting state
fromSlide.dataset.autoAnimate = 'pending';
toSlide.dataset.autoAnimate = 'pending';
// Flag the navigation direction, needed for fragment buildup
animationOptions.slideDirection = toSlideIndex > fromSlideIndex ? 'forward' : 'backward';
// If the from-slide is hidden because it has moved outside
// the view distance, we need to temporarily show it while
// measuring
let fromSlideIsHidden = fromSlide.style.display === 'none';
if( fromSlideIsHidden ) fromSlide.style.display = this.Reveal.getConfig().display;
// Inject our auto-animate styles for this transition
let css = this.getAutoAnimatableElements( fromSlide, toSlide ).map( elements => {
return this.autoAnimateElements( elements.from, elements.to, elements.options || {}, animationOptions, autoAnimateCounter++ );
} );
if( fromSlideIsHidden ) fromSlide.style.display = 'none';
// Animate unmatched elements, if enabled
if( toSlide.dataset.autoAnimateUnmatched !== 'false' && this.Reveal.getConfig().autoAnimateUnmatched === true ) {
// Our default timings for unmatched elements
let defaultUnmatchedDuration = animationOptions.duration * 0.8,
defaultUnmatchedDelay = animationOptions.duration * 0.2;
this.getUnmatchedAutoAnimateElements( toSlide ).forEach( unmatchedElement => {
let unmatchedOptions = this.getAutoAnimateOptions( unmatchedElement, animationOptions );
let id = 'unmatched';
// If there is a duration or delay set specifically for this
// element our unmatched elements should adhere to those
if( unmatchedOptions.duration !== animationOptions.duration || unmatchedOptions.delay !== animationOptions.delay ) {
id = 'unmatched-' + autoAnimateCounter++;
css.push( `[data-auto-animate="running"] [data-auto-animate-target="${id}"] { transition: opacity ${unmatchedOptions.duration}s ease ${unmatchedOptions.delay}s; }` );
}
unmatchedElement.dataset.autoAnimateTarget = id;
}, this );
// Our default transition for unmatched elements
css.push( `[data-auto-animate="running"] [data-auto-animate-target="unmatched"] { transition: opacity ${defaultUnmatchedDuration}s ease ${defaultUnmatchedDelay}s; }` );
}
// Setting the whole chunk of CSS at once is the most
// efficient way to do this. Using sheet.insertRule
// is multiple factors slower.
this.autoAnimateStyleSheet.innerHTML = css.join( '' );
// Start the animation next cycle
requestAnimationFrame( () => {
if( this.autoAnimateStyleSheet ) {
// This forces our newly injected styles to be applied in Firefox
getComputedStyle( this.autoAnimateStyleSheet ).fontWeight;
toSlide.dataset.autoAnimate = 'running';
}
} );
this.Reveal.dispatchEvent({
type: 'autoanimate',
data: {
fromSlide,
toSlide,
sheet: this.autoAnimateStyleSheet
}
});
}
}
/**
* Rolls back all changes that we've made to the DOM so
* that as part of animating.
*/
reset() {
// Reset slides
queryAll( this.Reveal.getRevealElement(), '[data-auto-animate]:not([data-auto-animate=""])' ).forEach( element => {
element.dataset.autoAnimate = '';
} );
// Reset elements
queryAll( this.Reveal.getRevealElement(), '[data-auto-animate-target]' ).forEach( element => {
delete element.dataset.autoAnimateTarget;
} );
// Remove the animation sheet
if( this.autoAnimateStyleSheet && this.autoAnimateStyleSheet.parentNode ) {
this.autoAnimateStyleSheet.parentNode.removeChild( this.autoAnimateStyleSheet );
this.autoAnimateStyleSheet = null;
}
}
/**
* Creates a FLIP animation where the `to` element starts out
* in the `from` element position and animates to its original
* state.
*
* @param {HTMLElement} from
* @param {HTMLElement} to
* @param {Object} elementOptions Options for this element pair
* @param {Object} animationOptions Options set at the slide level
* @param {String} id Unique ID that we can use to identify this
* auto-animate element in the DOM
*/
autoAnimateElements( from, to, elementOptions, animationOptions, id ) {
// 'from' elements are given a data-auto-animate-target with no value,
// 'to' elements are are given a data-auto-animate-target with an ID
from.dataset.autoAnimateTarget = '';
to.dataset.autoAnimateTarget = id;
// Each element may override any of the auto-animate options
// like transition easing, duration and delay via data-attributes
let options = this.getAutoAnimateOptions( to, animationOptions );
// If we're using a custom element matcher the element options
// may contain additional transition overrides
if( typeof elementOptions.delay !== 'undefined' ) options.delay = elementOptions.delay;
if( typeof elementOptions.duration !== 'undefined' ) options.duration = elementOptions.duration;
if( typeof elementOptions.easing !== 'undefined' ) options.easing = elementOptions.easing;
let fromProps = this.getAutoAnimatableProperties( 'from', from, elementOptions ),
toProps = this.getAutoAnimatableProperties( 'to', to, elementOptions );
// Maintain fragment visibility for matching elements when
// we're navigating forwards, this way the viewer won't need
// to step through the same fragments twice
if( to.classList.contains( 'fragment' ) ) {
// Don't auto-animate the opacity of fragments to avoid
// conflicts with fragment animations
delete toProps.styles['opacity'];
if( from.classList.contains( 'fragment' ) ) {
let fromFragmentStyle = ( from.className.match( FRAGMENT_STYLE_REGEX ) || [''] )[0];
let toFragmentStyle = ( to.className.match( FRAGMENT_STYLE_REGEX ) || [''] )[0];
// Only skip the fragment if the fragment animation style
// remains unchanged
if( fromFragmentStyle === toFragmentStyle && animationOptions.slideDirection === 'forward' ) {
to.classList.add( 'visible', 'disabled' );
}
}
}
// If translation and/or scaling are enabled, css transform
// the 'to' element so that it matches the position and size
// of the 'from' element
if( elementOptions.translate !== false || elementOptions.scale !== false ) {
let presentationScale = this.Reveal.getScale();
let delta = {
x: ( fromProps.x - toProps.x ) / presentationScale,
y: ( fromProps.y - toProps.y ) / presentationScale,
scaleX: fromProps.width / toProps.width,
scaleY: fromProps.height / toProps.height
};
// Limit decimal points to avoid 0.0001px blur and stutter
delta.x = Math.round( delta.x * 1000 ) / 1000;
delta.y = Math.round( delta.y * 1000 ) / 1000;
delta.scaleX = Math.round( delta.scaleX * 1000 ) / 1000;
delta.scaleX = Math.round( delta.scaleX * 1000 ) / 1000;
let translate = elementOptions.translate !== false && ( delta.x !== 0 || delta.y !== 0 ),
scale = elementOptions.scale !== false && ( delta.scaleX !== 0 || delta.scaleY !== 0 );
// No need to transform if nothing's changed
if( translate || scale ) {
let transform = [];
if( translate ) transform.push( `translate(${delta.x}px, ${delta.y}px)` );
if( scale ) transform.push( `scale(${delta.scaleX}, ${delta.scaleY})` );
fromProps.styles['transform'] = transform.join( ' ' );
fromProps.styles['transform-origin'] = 'top left';
toProps.styles['transform'] = 'none';
}
}
// Delete all unchanged 'to' styles
for( let propertyName in toProps.styles ) {
const toValue = toProps.styles[propertyName];
const fromValue = fromProps.styles[propertyName];
if( toValue === fromValue ) {
delete toProps.styles[propertyName];
}
else {
// If these property values were set via a custom matcher providing
// an explicit 'from' and/or 'to' value, we always inject those values.
if( toValue.explicitValue === true ) {
toProps.styles[propertyName] = toValue.value;
}
if( fromValue.explicitValue === true ) {
fromProps.styles[propertyName] = fromValue.value;
}
}
}
let css = '';
let toStyleProperties = Object.keys( toProps.styles );
// Only create animate this element IF at least one style
// property has changed
if( toStyleProperties.length > 0 ) {
// Instantly move to the 'from' state
fromProps.styles['transition'] = 'none';
// Animate towards the 'to' state
toProps.styles['transition'] = `all ${options.duration}s ${options.easing} ${options.delay}s`;
toProps.styles['transition-property'] = toStyleProperties.join( ', ' );
toProps.styles['will-change'] = toStyleProperties.join( ', ' );
// Build up our custom CSS. We need to override inline styles
// so we need to make our styles vErY IMPORTANT!1!!
let fromCSS = Object.keys( fromProps.styles ).map( propertyName => {
return propertyName + ': ' + fromProps.styles[propertyName] + ' !important;';
} ).join( '' );
let toCSS = Object.keys( toProps.styles ).map( propertyName => {
return propertyName + ': ' + toProps.styles[propertyName] + ' !important;';
} ).join( '' );
css = '[data-auto-animate-target="'+ id +'"] {'+ fromCSS +'}' +
'[data-auto-animate="running"] [data-auto-animate-target="'+ id +'"] {'+ toCSS +'}';
}
return css;
}
/**
* Returns the auto-animate options for the given element.
*
* @param {HTMLElement} element Element to pick up options
* from, either a slide or an animation target
* @param {Object} [inheritedOptions] Optional set of existing
* options
*/
getAutoAnimateOptions( element, inheritedOptions ) {
let options = {
easing: this.Reveal.getConfig().autoAnimateEasing,
duration: this.Reveal.getConfig().autoAnimateDuration,
delay: 0
};
options = extend( options, inheritedOptions );
// Inherit options from parent elements
if( element.parentNode ) {
let autoAnimatedParent = closest( element.parentNode, '[data-auto-animate-target]' );
if( autoAnimatedParent ) {
options = this.getAutoAnimateOptions( autoAnimatedParent, options );
}
}
if( element.dataset.autoAnimateEasing ) {
options.easing = element.dataset.autoAnimateEasing;
}
if( element.dataset.autoAnimateDuration ) {
options.duration = parseFloat( element.dataset.autoAnimateDuration );
}
if( element.dataset.autoAnimateDelay ) {
options.delay = parseFloat( element.dataset.autoAnimateDelay );
}
return options;
}
/**
* Returns an object containing all of the properties
* that can be auto-animated for the given element and
* their current computed values.
*
* @param {String} direction 'from' or 'to'
*/
getAutoAnimatableProperties( direction, element, elementOptions ) {
let config = this.Reveal.getConfig();
let properties = { styles: [] };
// Position and size
if( elementOptions.translate !== false || elementOptions.scale !== false ) {
let bounds;
// Custom auto-animate may optionally return a custom tailored
// measurement function
if( typeof elementOptions.measure === 'function' ) {
bounds = elementOptions.measure( element );
}
else {
if( config.center ) {
// More precise, but breaks when used in combination
// with zoom for scaling the deck ¯\_(ツ)_/¯
bounds = element.getBoundingClientRect();
}
else {
let scale = this.Reveal.getScale();
bounds = {
x: element.offsetLeft * scale,
y: element.offsetTop * scale,
width: element.offsetWidth * scale,
height: element.offsetHeight * scale
};
}
}
properties.x = bounds.x;
properties.y = bounds.y;
properties.width = bounds.width;
properties.height = bounds.height;
}
const computedStyles = getComputedStyle( element );
// CSS styles
( elementOptions.styles || config.autoAnimateStyles ).forEach( style => {
let value;
// `style` is either the property name directly, or an object
// definition of a style property
if( typeof style === 'string' ) style = { property: style };
if( typeof style.from !== 'undefined' && direction === 'from' ) {
value = { value: style.from, explicitValue: true };
}
else if( typeof style.to !== 'undefined' && direction === 'to' ) {
value = { value: style.to, explicitValue: true };
}
else {
// Use a unitless value for line-height so that it inherits properly
if( style.property === 'line-height' ) {
value = parseFloat( computedStyles['line-height'] ) / parseFloat( computedStyles['font-size'] );
}
if( isNaN(value) ) {
value = computedStyles[style.property];
}
}
if( value !== '' ) {
properties.styles[style.property] = value;
}
} );
return properties;
}
/**
* Get a list of all element pairs that we can animate
* between the given slides.
*
* @param {HTMLElement} fromSlide
* @param {HTMLElement} toSlide
*
* @return {Array} Each value is an array where [0] is
* the element we're animating from and [1] is the
* element we're animating to
*/
getAutoAnimatableElements( fromSlide, toSlide ) {
let matcher = typeof this.Reveal.getConfig().autoAnimateMatcher === 'function' ? this.Reveal.getConfig().autoAnimateMatcher : this.getAutoAnimatePairs;
let pairs = matcher.call( this, fromSlide, toSlide );
let reserved = [];
// Remove duplicate pairs
return pairs.filter( ( pair, index ) => {
if( reserved.indexOf( pair.to ) === -1 ) {
reserved.push( pair.to );
return true;
}
} );
}
/**
* Identifies matching elements between slides.
*
* You can specify a custom matcher function by using
* the `autoAnimateMatcher` config option.
*/
getAutoAnimatePairs( fromSlide, toSlide ) {
let pairs = [];
const codeNodes = 'pre';
const textNodes = 'h1, h2, h3, h4, h5, h6, p, li';
const mediaNodes = 'img, video, iframe';
// Explicit matches via data-id
this.findAutoAnimateMatches( pairs, fromSlide, toSlide, '[data-id]', node => {
return node.nodeName + ':::' + node.getAttribute( 'data-id' );
} );
// Text
this.findAutoAnimateMatches( pairs, fromSlide, toSlide, textNodes, node => {
return node.nodeName + ':::' + node.innerText;
} );
// Media
this.findAutoAnimateMatches( pairs, fromSlide, toSlide, mediaNodes, node => {
return node.nodeName + ':::' + ( node.getAttribute( 'src' ) || node.getAttribute( 'data-src' ) );
} );
// Code
this.findAutoAnimateMatches( pairs, fromSlide, toSlide, codeNodes, node => {
return node.nodeName + ':::' + node.innerText;
} );
pairs.forEach( pair => {
// Disable scale transformations on text nodes, we transition
// each individual text property instead
if( matches( pair.from, textNodes ) ) {
pair.options = { scale: false };
}
// Animate individual lines of code
else if( matches( pair.from, codeNodes ) ) {
// Transition the code block's width and height instead of scaling
// to prevent its content from being squished
pair.options = { scale: false, styles: [ 'width', 'height' ] };
// Lines of code
this.findAutoAnimateMatches( pairs, pair.from, pair.to, '.hljs .hljs-ln-code', node => {
return node.textContent;
}, {
scale: false,
styles: [],
measure: this.getLocalBoundingBox.bind( this )
} );
// Line numbers
this.findAutoAnimateMatches( pairs, pair.from, pair.to, '.hljs .hljs-ln-numbers[data-line-number]', node => {
return node.getAttribute( 'data-line-number' );
}, {
scale: false,
styles: [ 'width' ],
measure: this.getLocalBoundingBox.bind( this )
} );
}
}, this );
return pairs;
}
/**
* Helper method which returns a bounding box based on
* the given elements offset coordinates.
*
* @param {HTMLElement} element
* @return {Object} x, y, width, height
*/
getLocalBoundingBox( element ) {
const presentationScale = this.Reveal.getScale();
return {
x: Math.round( ( element.offsetLeft * presentationScale ) * 100 ) / 100,
y: Math.round( ( element.offsetTop * presentationScale ) * 100 ) / 100,
width: Math.round( ( element.offsetWidth * presentationScale ) * 100 ) / 100,
height: Math.round( ( element.offsetHeight * presentationScale ) * 100 ) / 100
};
}
/**
* Finds matching elements between two slides.
*
* @param {Array} pairs List of pairs to push matches to
* @param {HTMLElement} fromScope Scope within the from element exists
* @param {HTMLElement} toScope Scope within the to element exists
* @param {String} selector CSS selector of the element to match
* @param {Function} serializer A function that accepts an element and returns
* a stringified ID based on its contents
* @param {Object} animationOptions Optional config options for this pair
*/
findAutoAnimateMatches( pairs, fromScope, toScope, selector, serializer, animationOptions ) {
let fromMatches = {};
let toMatches = {};
[].slice.call( fromScope.querySelectorAll( selector ) ).forEach( ( element, i ) => {
const key = serializer( element );
if( typeof key === 'string' && key.length ) {
fromMatches[key] = fromMatches[key] || [];
fromMatches[key].push( element );
}
} );
[].slice.call( toScope.querySelectorAll( selector ) ).forEach( ( element, i ) => {
const key = serializer( element );
toMatches[key] = toMatches[key] || [];
toMatches[key].push( element );
let fromElement;
// Retrieve the 'from' element
if( fromMatches[key] ) {
const primaryIndex = toMatches[key].length - 1;
const secondaryIndex = fromMatches[key].length - 1;
// If there are multiple identical from elements, retrieve
// the one at the same index as our to-element.
if( fromMatches[key][ primaryIndex ] ) {
fromElement = fromMatches[key][ primaryIndex ];
fromMatches[key][ primaryIndex ] = null;
}
// If there are no matching from-elements at the same index,
// use the last one.
else if( fromMatches[key][ secondaryIndex ] ) {
fromElement = fromMatches[key][ secondaryIndex ];
fromMatches[key][ secondaryIndex ] = null;
}
}
// If we've got a matching pair, push it to the list of pairs
if( fromElement ) {
pairs.push({
from: fromElement,
to: element,
options: animationOptions
});
}
} );
}
/**
* Returns a all elements within the given scope that should
* be considered unmatched in an auto-animate transition. If
* fading of unmatched elements is turned on, these elements
* will fade when going between auto-animate slides.
*
* Note that parents of auto-animate targets are NOT considered
* unmatched since fading them would break the auto-animation.
*
* @param {HTMLElement} rootElement
* @return {Array}
*/
getUnmatchedAutoAnimateElements( rootElement ) {
return [].slice.call( rootElement.children ).reduce( ( result, element ) => {
const containsAnimatedElements = element.querySelector( '[data-auto-animate-target]' );
// The element is unmatched if
// - It is not an auto-animate target
// - It does not contain any auto-animate targets
if( !element.hasAttribute( 'data-auto-animate-target' ) && !containsAnimatedElements ) {
result.push( element );
}
if( element.querySelector( '[data-auto-animate-target]' ) ) {
result = result.concat( this.getUnmatchedAutoAnimateElements( element ) );
}
return result;
}, [] );
}
}